The development of the commerical culture of animals in aquaculture, especially of crustacea, has been accompanied by the occurrence of infectious and noninfectious diseases. Many of the important diseases suffered by, for example, penaeid shrimps, are caused by organisms which are ubiquitous and have been established in all the major penaeid culture areas of the world, e.g. in Japan, Korea, Taiwan, the Philippines, Tahiti, Indonesia, Thailand, Malaysia, India, the Caribbean, Brazil, Mexico, Panama, Ecuador, Colombia, the U.S.A., Australia, France, Spain and Italy.
With increasing density and production level of penaeid shrimps diseases have broken out rapidly. Outbreaks of fungal infections, e.g. Lagenidium and Sirolpidium, bacterial attacks, e.g. Vibrio and Aeromonas, and even viruses, e.g. Baculovirus, are frequent in hatcheries, most of these problems being due to insufficient control of the rearing systems and absence of sanitary procedures as in terrestrial husbandry (disinfection, regular dry-out, separate equipment for each tank and separate rooms for maturation, spawning, hatching and larval rearing). The result is a weakening of the larvae and a lowering of their resistance to disease. Although antifungal agents such as trifluralin and Malachite green, and antibiotics used sparingly in the tanks have achieved some success the need to have a dry-out every six to eight weeks of production in order to eliminate bacterial strains which have become increasingly resistant and pathogenic has not been avoided.